Power tool with additional function

ABSTRACT

The present invention provides an electric tool which includes an electrical device, such as a radio, as an additional function, and is lightweight and easy to handle for operation. The electric tool includes a lithium-ion secondary battery as a power supply, and is equipped with an electrical device, which operates on small electric power supplied from the lithium-ion secondary battery.

TECHNICAL FIELD

The present invention relates to electric tools, such as electricdrivers for use in screw fastening work.

BACKGROUND ART

Electric tools, such as electric drivers, for use in the screw fasteningwork have hitherto been used primarily in construction sites and thelike for business purposes as they permit significant improvement inoperative efficiency. In recent years, they are available at homeimprovement centers and the like, and have come to be generally used forhome carpentry.

In home carpentry, the price of an electric tool per one operation isexpensive because of a low frequency of the use thereof. Thus, electrictools have been required to provide some sort of added value. Moreover,since portable radios are often brought into working operation sites,there have been proposed configurations in which a radio is added to acharger for charging a battery of an electric tool (e.g. JapaneseLaid-Open Patent Publication No. 2000-92726: corresponding U.S. Pat. No.6,427,070 and U.S. Pat. No. 6,496,688). However, in operation sites usedby operation workers, commercial power supplies are often not prepared.Further, it is often the case that a customer having ordered workingoperations bears electrical expenses thereof. For these reasons, in manycases, spare batteries are prepared in working operation sites andbatteries are not charged. It is therefore necessary to add some sort ofvalue not to a charger, but to an electric tool itself.

Since a person holds an electric tool with his hand while at work,however, it needs to-be light enough for portability. This has made itimpossible to add an additional function which would cause a weightincrease of an electric tool.

DISCLOSURE OF INVENTION

In view of the aforesaid conventional problem, an object of the presentinvention is to provide an electric tool which is lightweight and easyto handle for operation, even with an addition function added thereto.

For the purpose of achieving the above object, an electric tool equippedwith an additional function in accordance with the present invention isone comprising a lithium-ion secondary battery as a power supply,characterized in that the electric tool is equipped with an electricaldevice as an additional function, which operates on small electric powersupplied from the lithium-ion secondary battery.

Since lithium-ion secondary batteries are lighter than nickel-cadmiumstorage batteries and nickel-metal hydride storage batteries, which haveconventionally been used for electric tools, it is possible to equip alithium-ion secondary battery with an additional function having aweight corresponding to a weight difference between either of theaforesaid two sorts of storage batteries and a lithium-ion secondarybattery. For example, ten nickel-metal hydride storage batteries ofsub-C size, having a total weight of 550 g, are used in an electricdriver. When these batteries are replaced with lithium-ion secondarybatteries, eight lithium-ion secondary batteries of 18650 size aresufficient to obtain the equivalent total battery electric power. Inthis case, the total weight is 320 g, with a 200-g weight margin.

Further, according to the present invention, since the additionalfunction operates on small electric power, the electric power of thebattery as the power supply is not consumed so much. Also, there is adisadvantage peculiar to lithium-ion secondary batteries. Thedisadvantage is that, when a lithium-ion secondary batter is stored in afully charged state, i.e., when the power of a fully charged lithium-ionsecondary battery is not consumed, the battery will deterioratespecifically. However, in the case of the electric tool equipped with anadditional function in accordance with the present invention, even whenthe electric tool is not used, the additional function consumes thepower of the battery, thereby producing the effect of preventing thedisadvantage.

Furthermore, it is preferable that the electrical device continue toconsume small electric power supplied from the lithium-ion secondarybattery when the electrical device is electrically connected to thelithium-ion secondary battery. This can be exemplified by electricaldevices, such as clocks, assumed to usually keep operating and thus keepconsuming small electric power. Another preferable example may beelectrical devices, such as radios, that keep consuming small electricpower through a quiescent current or the like even when they areswitched off. The continuous consumption of the battery electric powerby the electrical device results in more certain generation of theeffect of inhibiting the disadvantage of specific deterioration of thelithium-ion secondary battery during storage in a sully charged state.

It is further preferable that the lithium-ion secondary battery beincluded in a battery pack, and that the electrical device be installedintegrally in the battery pack. This configuration of integrating theelectrical device and the lithium-ion secondary battery with the batterypack enables continuous consumption of battery electric power by theelectrical device, even with the battery pack (lithium-ion secondarybattery) removed from the main body of the electric tool, and it isthereby possible to continuously generate the effect of inhibiting thedisadvantage of specific deterioration of the lithium-ion secondarybattery during storage in a sully charged state.

A brief description will be given of the specific deterioration oflithium-ion secondary batteries. Lithium-ion secondary batteries oftencause the following phenomenon as their general properties: when thebattery is stored at a high temperature, an active material reacts withan electrolyte to form a coating film on the active material surface ofthe battery, or gas is generated through the reaction to cause expansionof the battery.

This phenomenon is related to the depth of battery charge, thetemperature at which the battery is allowed to stand, and the time forwhich the battery is allowed to stand. Specifically, the larger thedepth of the battery charge, or the higher the temperature at which thebattery is allowed to stand, or the longer the time for which thebattery is allowed to stand at a high temperature, the more markedly thephenomenon occurs. When a battery is allowed to stand in a fully chargedstate at 40 to 50° C. for about a week, for example, deterioration indischarge characteristic of the battery associated with the formation ofa coating film, and deterioration in discharge characteristic and cyclelife characteristic due to the battery expansion, are markedly observed.

In the present invention, this phenomenon has been described as specificdeterioration. According to the present invention, it is possible toprevent the specific deterioration from occurring even in the case wherethe electric tool is allowed to stand in a high-temperature atmosphereat about 40 to 70° C. for a long period of time.

It is also preferable that the electric tool be an electric driver. Anelectric driver is often carried with a person by means of a portablebelt even during a working operation not using the electric driver, andhence has an advantage of making an additional function well utilized.

It is also preferable that the electrical device comprise at least oneof a radio, clock and light. It is further preferable that theelectrical device comprise a display unit, and in particular that thedisplay unit comprise at least one of a function of displaying theremaining power of a battery, and a clock function.

These electrical devices are in regular use in working operation sitesand at homes, and therefore highly convenient as additional functionsfor users of electric tools. Further, the installation of theseelectrical devices in electric tools as additional functions cangenerate the effect of allowing users of those electric tools to handlethe electric tools carefully. Moreover, it is particularly favorable toinstall a display unit having a function of displaying the remainingpower of a battery, since this makes it possible to predict when thebattery needs to be replaced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic oblique view of an electric driver equipped with aradio, in accordance with Embodiment 1 of the present invention.

FIG. 2 is a schematic oblique view of an electric driver equipped with aclock, in accordance with Embodiment 2 of the present invention.

FIG. 3 is a schematic oblique view of an electric driver equipped with alight, in accordance with Embodiment 3 of the present invention.

FIG. 4 is a schematic oblique view of an electric driver equipped with adisplay unit having a function of displaying the remaining power of abattery, and a clock function, in accordance with Embodiment 4 of thepresent invention.

FIG. 5 is a schematic block diagram representing a constitutionalexample of electrical connection of an electric tool equipped with anadditional function in each Embodiment.

FIG. 6 is a schematic block diagram representing an example of a clockas an electrical device, in accordance with Embodiment 2 of the presentinvention.

FIG. 7 is a schematic block diagram representing an example of a lightas an electrical device, in accordance with Embodiment 3 of the presentinvention.

FIG. 8 is a schematic block diagram representing an example of a displayunit as an electrical device, in accordance with Embodiment 4 of thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, embodiments of the present invention will be describedin detail based on specific examples, using attached drawings.

EMBODIMENT 1

FIG. 1 shows a schematic oblique view of an electric driver equippedwith a radio based on Embodiment 1 of the present invention. A housing 1with a rotation drive built therein is provided with a handle 2. Abattery pack 3 is provided on the end of the handle 2, which engages alatch 4. The handle 2 is also provided with a switch trigger 5, andwhile triggering the switch trigger 5, a driver bit 7 which is fixed bya one-touch holder 6 can be rotated. The rotating direction at this timecan be varied by a push button 8.

In the present embodiment, in addition to the lithium-ion secondarybattery, a radio circuit is housed in the battery pack 3, and the sidesurface of the battery pack 3 is provided with a power-on switch 9, avolume switch 10, and a tuner switch 11, of the radio. When the power-onswitch 9 is turned on and then the volume switch 10 and the tuner switchare suitably adjusted, a sound comes from a speaker 12.

Simultaneously, small electric power supplied from the lithium-ionsecondary battery is consumed by the use of this radio, even when theelectric driver is not in use, thereby enabling inhibition of thedisadvantage of specific deterioration of the lithium-ion secondarybattery during storage in a fully charged state.

In the present embodiment, since the battery pack 3 is added with aradio, the radio is usable even when removed from the electric drivermain body. In other words, the radio can consume small electric powersupplied from the lithium-ion secondary battery even when the batterypack 3 has been removed from the electric driver main body. This caninhibit the disadvantage of specific deterioration of the lithium-ionsecondary battery during storage in a fully charged state.

In the present embodiment, the electric tool, the lithium-ion secondarybattery and an additional function portion comprising the electricaldevice are suitably connected electrically in the electric tool equippedwith an additional function. One of the examples thereof will bedescribed below, using FIG. 5.

FIG. 5 is a schematic block diagram representing a constitutionalexample of electrical connection of an electric tool (electric driver)50 equipped with an additional function in accordance with the presentembodiment (and also applicable to the other embodiments). In FIG. 5,the electric tool 50 equipped with an additional function comprises anelectric tool (electric driver) main body portion 51, and a lithium-ionsecondary battery portion 52 that is electrically connected to theelectric tool main body portion 51, and for supplying electric power tothe electric tool main body portion 51. The electric tool 50 equippedwith an additional function further comprises an additional functionportion which comprises: (1) a small electric power output portion 53that is electrically connected to the lithium-ion secondary batteryportion 52, and for outputting small electric power on reception ofelectric power from the lithium-ion secondary battery; and (2) anelectrical device (radio) 54 that is electrically connected to the smallelectric power output portion 53 and electrically driven by smallelectric power supplied from the small electric power output portion 53.The electrical device (radio) 54 comprises a radio circuit portion 56driven by small electric power supplied from the small electric poweroutput portion 53, and a radio main body portion 57 (a speaker 12 etc.)connected to the radio circuit portion 56.

At the midway point of an electrical connection wire between theelectric tool main body portion 51 and the lithium-ion secondary battery52, an electric connector 55 is provided if required. This permits sucha configuration that the lithium-ion secondary battery 52, or a batterypack containing the lithium-ion secondary battery 52, the small electricpower output portion 53 and the electrical device (radio), can beremoved from the electric tool main body portion 51 to be used as aradio.

It is preferable in the present embodiment in the case where the radiois electrically connected to the lithium-ion secondary battery that theradio consume small electric power supplied from the lithium-ionsecondary battery through a quiescent current even when switched off.This is because such consumption of small electric power can certainlyinhibit the disadvantage of specific deterioration of the lithium-ionsecondary battery during storage in a fully charged state.

In FIG. 5 and the present embodiment, it is assumed that the electricaldevice 54 is a radio. However, this constitutional example of FIG. 5 isnot limited to the present embodiment, but in common with otherEmbodiments 2 to 4 as later described. In the present embodiment, aradio is used as the electrical device; however, in Embodiments 2 to 4,a clock, a light and a display unit (e.g. a display of the remainingpower of a battery, and a clock display) are used respectively as theelectrical device in place of the radio. Except that, the sameconfiguration to that in FIG. 5 as well as the present embodiment isapplied.

Further, a radio circuit portion 56 and a speaker are operated on smallelectric power supplied from the lithium-ion secondary battery. Thissmall electric power is in an amount ignorable as compared with electricpower required for the rotation drive of the electric driver main body.Moreover, the lithium-ion secondary battery within the battery pack 3 ischarged when its amount of electricity has decreased to a certain degreein order to normally drive the rotation drive. This can produce thefollowing effect: For example, in the case where a radio including abattery as an independent power source is not electrically connected tothe battery pack 3, but simply installed therein mechanically, there areproblems in that the battery is dead when a person wants to listen tothe radio, or in that it takes all the trouble to replace the powersupply just for listening to the radio. As opposed to this, the presentembodiment has the effect of eliminating such problems.

It should be noted that the radio is installed in the battery pack 3 inthe present embodiment. It is thereby possible, as thus described, toobtain the effect generated by the integration of the lithium-ionsecondary battery with the radio even when the battery pack has beenremoved from the electric driver main body. When such an effect is notrequired, however, the radio may be installed in the electric drivermain body, such as the housing 1.

EMBODIMENT 2

FIG. 2 shows a schematic oblique view of an electric driver equippedwith a clock in accordance with Embodiment 2 of the present invention.In FIG. 2, elements with the same numeral signals as those elements inFIG. 1 have the same names and functions as those elements in FIG. 1.

In the present embodiment, in addition to the lithium-ion secondarybattery, a clock-driving circuit is housed in the battery pack 3, andthe side surface of the battery pack 3 is provided with a clock(electrical device) 14. This indicates the time.

This clock at the same time enables inhibition of the disadvantage ofspecific deterioration of the lithium-ion secondary battery duringstorage in a fully charged state, even when the electric driver is notused.

A constitutional example of electrical connection of an electric driverequipped with a clock based on the present embodiment is one obtained byreplacing the electrical device (radio) 54 in FIG. 5 with a clock 14 asshown in the schematic block diagram in FIG. 6. Weak current poweroutput in FIG. 6 corresponds to output from the small electric poweroutput portion 53 in FIG. 5. In FIG. 6, the clock 14 comprises aclock-driving circuit portion 66 that is driven by small electric powerfrom the lithium-ion secondary battery, and a clock display unit 67.

In the present embodiment, since the battery pack 3 is added with aclock 14, the clock 14 can be used after the battery pack 3 is removedfrom the electric driver main body portion (electric tool main bodyportion). In other words, the clock can consume small electric powersupplied from the lithium-ion secondary battery even when the batterypack 3 has been removed from the electric driver main body. This caninhibit the disadvantage of specific deterioration of the lithium-ionsecondary battery during storage in a fully charged state.

Further, small electric power supplied from the lithium-ion secondarybattery, operating the clock-driving circuit, is in an amount ignorableas compared with electric power required for the rotation drive of theelectric driver main body. Moreover, the lithium-ion secondary batterywithin the battery pack 3 is charged when its amount of electricity hasdecreased to a certain degree in order to normally drive the rotationdrive. This can produce the following effect: For example, in the casewhere a clock including a battery as an independent power source is notelectrically connected to the battery pack 3, but simply installedtherein mechanically, there are problems in that the battery abruptlygoes dead, or in that it takes all the trouble to replace the powersupply just for activating the clock. As opposed to this, the presentembodiment has the effect of eliminating such problems.

It should be noted that the clock is installed in the battery pack 3 inthe present embodiment. It is thereby possible, as thus described, toobtain the effect generated by the integration of the lithium-ionsecondary battery with the clock even when the battery pack has beenremoved from the electric driver main body. When such an effect is notrequired, however, the clock may be installed in the electric drivermain body, such as the housing 1.

EMBODIMENT 3

FIG. 3 shows a schematic oblique view of an electric driver equippedwith a light in accordance with an embodiment of the present invention.In FIG. 3, elements with the same numeral signals as those elements inFIG. 1 have the same names and functions as those elements in FIG. 1.

In the present embodiment, the housing 1 is provided with a light(electrical device) 15 whose power supply is the lithium-ion secondarybattery, and the handle 2 is added with a light switch 16. Thisconfiguration allows this light to be used like a flashlight. When aperson works at a dark place, for example, under an automobile, theperson can shine light on necessary places such as screws, so that theperson can see the places clearly.

The use of this light at the same time enables inhibition of thedisadvantage of specific deterioration of the lithium-ion secondarybattery during storage in a fully charged state, even when the electricdriver is not used.

A constitutional example of electrical connection of an electric driverequipped with a light based on the present embodiment is one obtained byreplacing the electrical device (radio) 54 in FIG. 5 with a light 15 asshown in the schematic block diagram in FIG. 7. Weak current poweroutput in FIG. 7 corresponds to output from the small electric poweroutput portion 53 in FIG. 5.

The light 15 operates on small electric power supplied from thelithium-ion secondary battery. This small electric power is in an amountignorable as compared with electric power required for the rotationdrive of the electric driver main body. Moreover, the lithium-ionsecondary battery within the battery pack 3 is charged when its amountof electricity has decreased to a certain degree in order to normallydrive the rotation drive. This can produce the following effect: Forexample, in the case where a light including a battery as an independentpower source is not electrically connected to the battery pack 3, butsimply installed therein mechanically, there are problems in that thepower abruptly goes dead, or in that it takes all the trouble to replacethe power supply just for turning on the light. As opposed to this, thepresent embodiment has the effect of eliminating such problems.

It should be noted that, in the present embodiment, two lights 15 areinstalled in the upper part of the housing 1; however, only one lightmay be applied, or a plurality of lights may be installed on the side ofthe housing 1. The light 15 can also be installed integrally on the sidesurface of the battery pack 3. Therefore, the light can consume smallelectric power supplied from the lithium-ion secondary battery even whenthe battery pack 3 has been removed from the electric driver main body,thereby enabling inhibition of the disadvantage of specificdeterioration of the lithium-ion secondary battery during storage in afully charged state.

EMBODIMENT 4

FIG. 4 shows an oblique view of an electric driver equipped with adisplay unit having a function of displaying the remaining power of abattery, as well as a clock function, in accordance with an embodimentof the present invention. In FIG. 4, elements with the same numeralsignals as those elements in FIG. 1 have the same names and functions asthose elements in FIG. 1.

In the present embodiment, in addition to the lithium-ion secondarybattery, a circuit of detecting remaining battery power and a clockcircuit are housed in the battery pack 3, and the side surface of thebattery pack 3 is provided with a display unit 19 equipped with aremaining battery power display portion 17 and a clock display portion18. The side surface is further equipped with time-setting 20 and analarm-setting 21. This shows the time, and also when the lithium-ionsecondary battery needs to be replaced.

The use of this display unit also enables the inhibition of thedisadvantage of specific deterioration of the lithium-ion secondarybattery during storage in a fully charged state, even when the electricdriver is not used.

A constitutional example of electrical connection of an electric driverequipped with a display unit based on the present embodiment is oneobtained by replacing the electrical device (radio) 54 in FIG. 5 with adisplay unit 19 as shown in the schematic block diagram in FIG. 8. Weakcurrent power output in FIG. 8 corresponds to output from the smallelectric power output portion 53 in FIG. 5

In FIG. 8, the display unit 19 comprises: a remaining battery powerdetecting circuit portion 86 for detecting the remaining power of thelithium-ion secondary battery based on small electric power suppliedfrom the lithium-ion secondary battery; a remaining battery powerdisplay portion 17 for displaying the remaining power of the battery,which is detected by the detecting circuit portion 86; a clock circuitportion 88 driven by small electric power supplied from the lithium-ionsecondary battery; and a clock display portion 18 for displaying outputof the clock circuit portion.

In the present embodiment, since the battery pack 3 is added with thedisplay unit having a clock function comprising the clock circuitportion 88 and the clock display portion 18, the clock function, namelythe display unit, can be used even when having been removed from theelectric driver main body. In other words, the clock function, namelythe display unit, can consume small electric power supplied from thelithium-ion secondary battery even when the battery pack 3 has beenremoved from the electric driver main body. This can inhibit thedisadvantage of specific deterioration of the lithium-ion secondarybattery during storage in a fully charged state.

Further, the aforesaid circuits (the remaining battery power detectingcircuit portion 86 and clock circuit portion 88) operate on smallelectric power supplied from the lithium-ion secondary battery. Thissmall electric power is in an amount ignorable as compared with electricpower required for the rotation drive of the electric driver main body.Moreover, the lithium-ion secondary battery within the battery pack 3 ischarged when its amount of electricity has decreased to a certain degreein order to normally drive the rotation drive. This can produce thefollowing effect: For example, in the case where a display unitincluding a battery as an independent power source is not electricallyconnected to the battery pack 3, but simply installed thereinmechanically, there are problems in that the power abruptly goes dead,or in that it takes all the trouble to replace the power supply just foractivating the display unit. As opposed to this, the present embodimenthas the effect of eliminating such problems.

It should be noted that, in the present embodiment, the display unithaving a function of displaying the remaining power of a battery, aswell as a clock function, is installed in the battery pack 3. It isthereby possible, as thus described, to obtain the effect generated bythe integration of the lithium-ion secondary battery with the displayunit even when the battery pack has been removed from the electricdriver main body. When such an effect is not required, however, thedisplay unit may be installed in the electric driver main body, such asthe housing 1.

Industrial Applicability

As thus described, according to the electric tool equipped with anadditional function of the present invention, it is possible to utilizeand take enjoyment in an additional function, such as a radio, whileimproving portability. It is further possible to inhibit specificdeterioration peculiar to a lithium-ion secondary battery when thebattery is stored in a fully charged state. Moreover, with theelectrical device added, it becomes less likely that a tool is roughlyused as a substitute for a hammer, which is under the ban in aninstruction manual, thereby generating the effect of reducing thepossibility that users of electric tools make complaints againstmanufactures thereof.

1. An electric tool equipped with an additional function, said electrictool comprising a lithium-ion secondary battery to serve as a powersupply and an electrical device which operates on small electric powersupplied from said lithium-ion secondary battery.
 2. The electric toolequipped with an additional function in accordance with claim 1, whereinsaid electrical device keeps consuming said small electric powersupplied from said lithium-ion secondary battery when said electricaldevice is electrically connected to said lithium-ion secondary battery.3. The electric tool equipped with an additional function in accordancewith claim 1, further comprising a battery pack including saidlithium-ion secondary battery, said electrical device being installedintegrally in said battery pack.
 4. The electric tool equipped with anadditional function in accordance with claim 1, wherein said electrictool is an electric driver.
 5. The electric tool equipped with anadditional function in accordance with claim 1, wherein said electricaldevice comprises a radio.
 6. The electric tool equipped with anadditional function in accordance with claim 1, wherein said electricaldevice comprises a clock.
 7. The electric tool equipped with anadditional function in accordance with claim 1, wherein said electricaldevice comprises a light.
 8. The electric tool equipped with anadditional function in accordance with claim 1, wherein said electricaldevice comprises a display unit.
 9. The electric tool equipped with anadditional function in accordance with claim 8, wherein said displayunit has at least one of a function of displaying the remaining power ofsaid lithium-ion secondary battery, and a clock function.